1. Field of the Invention
This invention relates to a millimeter waveguide for transmitting millimeter waves and a circuit apparatus using the same.
2. Description of the Prior Art
A millimeter waveguide for transmitting millimeter waves is known. As a such a waveguide, a shielded membrane microstrip is disclosed in 1996 IEEE MTT-S Digest at pages 797 to 800.
FIG. 10 is a cross-sectional side view of this prior art millimeter waveguide.
Silicon dioxide 802 is formed on a silicon substrate 801 and a microstrip line 803 is formed on the silicon dioxide 802. The silicon substrate 801 is sandwiched by a carrier substrate 804 on which a metal is formed and a silicon substrate 805 subjected to micromachining processing, so that the microstrip line 803 is shielded.